Table 3. Biomass, sterigmatocystin, RS and antioxidant enzyme production in A. nidulans ΔnapA and OE : : napA mutants.
Strain and treatment | Physiological parameter* | |||||||||
Biomass (DCM†) production (g l−1) | Sterigmatocystin production [mg (g DCM)−1] | RS‡ production [pmol DCF (g DCM)−1] | Specific antioxidant enzyme activities | |||||||
Catalase [kat (kg protein−1)] | Glutathione peroxidase (GPx) [mkat (kg protein)−1] | |||||||||
0 h | 10 h | 24 h | 24 h | 10 h | 24 h | 10 h | 24 h | 10 h | 24 h | |
WT | 2.0±0.3 | 4.5±0.6 | 4.2±0.5 | 1.5±0.5 | 0.25±0.05 | 0.19±0.05 | 0.21±0.02 | 0.28±0.03§ | 0.54±0.05 | 0.31±0.03§ |
WT+tBOOH | 2.1±0.3 | 2.2±0.6¶ | 4.4±0.5§ | 3.1±1¶ | 27±5¶ | 0.52±0.06§¶ | 0.56±0.05¶ | 0.31±0.04§ | 0.68±0.05¶ | 0.28±0.03§ |
ΔnapA | 2.1±0.3 | 4.4±0.3 | 3.6±0.4§ | 1.4±0.5 | 0.41±0.06# | 0.47±0.07# | 0.12±0.02# | 0.20±0.03§# | 0.68±0.07# | 0.33±0.03§ |
ΔnapA+tBOOH | 2.1±0.2 | 1.8±0.3¶ | 3.4±0.4§# | 3.3±1¶ | 32±7¶ | 1.8±0.5§¶# | 0.31±0.03¶# | 0.28±0.03¶ | 0.76±0.08 | 0.65±0.07¶# |
Pyridoxine supplementation | ||||||||||
WT | 2.2±0.3 | 4.5±0.6 | 4.2±0.5 | 1.6±0.5 | 0.24±0.05 | 0.17±0.05 | 0.22±0.02 | 0.27±0.04 | 0.51±0.05 | 0.21±0.03§|| |
WT+tBOOH | 2.1±0.2 | 4.6±0.6|| | 4.0±0.5 | 3.0±1¶ | 19±4||¶ | 0.44±0.05§¶ | 0.39±0.02||¶ | 0.28±0.03§ | 0.63±0.05¶ | 0.23±0.03§ |
OE : : napA | 2.3±0.3 | 4.8±0.5 | 4.0±0.5 | 0.7±0.3** | 0.3±0.05 | 0.19±0.04§ | 0.19±0.02 | 0.26±0.03§ | 0.62±0.06** | 0.53±0.07** |
OE : : napA+tBOOH | 2.2±0.3 | 4.8±0.5 | 4.2±0.5 | 1.0±0.3¶** | 1.1±0.2¶** | 0.18±0.05§** | 0.21±0.02** | 0.25±0.03 | 0.68±0.06 | 0.47±0.07§** |
Mean±sd values calculated from three independent experiments are presented.
DCM, dry cell mass.
RS includes all intracellular oxidants which react to give rise to 2′,7′-dichlorofluorescein from from 2′,7′-dichlorofluorescin diacetate (Halliwell & Gutteridge, 2007).
||¶#**Significant differences (P<0.05, where P values were calculated using Student’s t test) between 10 and 24 h incubations (§), caused by pyridoxine (||) supplementation or tBOOH treatment (¶) or initiated by ΔnapA (#) or OE : : napA (**), respectively.